From 357bad7101df196d7f4ea3dc6ed9a6436afb022c Mon Sep 17 00:00:00 2001
From: Louie Lu <louie.lu@hopebaytech.com>
Date: Fri, 24 Feb 2017 11:59:49 +0800
Subject: [PATCH] bpo-29634: Reduce deque repeat execution when maxlen exist
 and size is not 1 (#255) (#255)

---
 Modules/_collectionsmodule.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 8615bf1d39..44e9e119ae 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -731,6 +731,10 @@ deque_inplace_repeat(dequeobject *deque, Py_ssize_t n)
     if (seq == NULL)
         return seq;
 
+    /* Reduce the number of repetitions when maxlen would be exceeded */
+    if (deque->maxlen >= 0 && n * size > deque->maxlen)
+        n = (deque->maxlen + size - 1) / size;
+
     for (i = 0 ; i < n-1 ; i++) {
         rv = deque_extend(deque, seq);
         if (rv == NULL) {
-- 
2.50.0